A Triple-Band Absorber With Wide Absorption Bandwidths Using an Impedance Matching Theory

This letter presents multi-band absorbers with wide absorption bandwidths based on impedance matching theory. A wideband absorber with good absorption performance is served as a matching load for multi-band bandpass frequency selective surface (FSS) filters. As a result, the reflection coefficients of the proposed absorbers are in high accordance with the counterparts of the original bandpass FSS filters. For demonstration, a triple-band absorber with wide absorption bandwidths is designed and fabricated by cascading a triple-band bandpass FSS filter and wideband absorber together. The simulated results reveal that the proposed absorber has wide fractional bandwidths of 5.2 %, 8.0 %, and 6.4%, which is experimentally validated by the measured results.